Fingerprint recognition sensor, display panel, and method for manufacturing fingerprint recognition sensor

Abstract

The present application discloses a fingerprint recognition sensor, a display panel and a method for manufacturing a fingerprint recognition sensor. The fingerprint recognition sensor includes a piezoelectric layer, an emission layer and a first isolation layer; the emission layer is arranged on one side of the piezoelectric layer, and includes a plurality of emission electrodes arranged at intervals along a first direction; the first isolation layer is arranged between the piezoelectric layer and the emission layer. Through the above arrangement, the first isolation layer can isolate the direct contact between the stripping liquid and the piezoelectric layer, prevent the piezoelectric layer from falling off during the manufacturing and use process, thereby improving the recognition accuracy of the fingerprint recognition sensor.

Description

Technical Field

[0001] The present application relates to the field of fingerprint recognition, and in particular to a fingerprint recognition sensor, a display panel, and a method for manufacturing the fingerprint recognition sensor. Background Art

[0002] With the continuous development of science and technology, fingerprint recognition technology has gradually been applied to people's daily life. Fingerprint recognition technology can achieve the function of identity recognition by comparing the detailed feature points of different fingerprints. Generally, fingerprint recognition technology can be divided into optical fingerprint recognition technology, silicon chip fingerprint recognition technology and ultrasonic fingerprint recognition technology.

[0003] At present, ultrasonic fingerprint recognition technology is a popular research direction for major manufacturers. The ultrasonic fingerprint recognition structure is mainly a three-layer structure, including a transmitting electrode, a receiving electrode, and a piezoelectric layer located between the two. When a driving voltage is applied to the transmitting electrode and the receiving electrode, the piezoelectric layer is excited by the voltage to produce an inverse piezoelectric effect, which generates vibrations and emits a first ultrasonic wave outward. After the first ultrasonic wave contacts the finger, it is reflected back by the finger as a second ultrasonic wave. Since the fingerprint includes valleys and ridges, the vibration intensity of the second ultrasonic wave reflected back to the piezoelectric layer by the fingerprint is different. At this time, the piezoelectric layer can convert the second ultrasonic wave into a voltage signal. The receiving electrode receives the piezoelectric signal and transmits it to the fingerprint calculation module. The position of the valleys and ridges in the fingerprint is determined according to the voltage signal, thereby realizing the fingerprint recognition function.

[0004] However, the above ultrasonic fingerprint recognition structure still has room for improvement in terms of accurate recognition. Summary of the invention

[0005] The present application provides a fingerprint recognition sensor, a display panel and a method for manufacturing the fingerprint recognition sensor, which can improve the recognition accuracy of the fingerprint recognition sensor.

[0006] According to a first aspect of the present application, a fingerprint recognition sensor is provided, the fingerprint recognition sensor comprising:

[0007] Piezoelectric layer;

[0008] An emitting layer, arranged on one side of the piezoelectric layer, comprising a plurality of emitting electrodes arranged at intervals along a first direction;

[0009] The first isolation layer is arranged between the piezoelectric layer and the emission layer.

[0010] Furthermore, the thickness of the first isolation layer is greater than or equal to 1000 angstroms and less than or equal to 6000 angstroms.

[0011] Furthermore, the dielectric constant of the first isolation layer is greater than or equal to 6 and less than or equal to 9.

[0012] Furthermore, the number of transmitting electrodes is greater than or equal to three.

[0013] Furthermore, the fingerprint recognition sensor further comprises an electrical signal generating device, wherein the electrical signal generating device is electrically connected to the emitting layer to control the electrical signal applied to the emitting electrode;

[0014] The electrical signal generating device sequentially applies electrical signals to the transmitting electrodes along the direction from the edge of the piezoelectric layer to the center of the piezoelectric layer, so that the ultrasonic wave generated by the piezoelectric layer is focused above the center of the piezoelectric layer.

[0015] Further, the emitting electrode extends along a second direction and exceeds first edges of the piezoelectric layer and the first isolation layer in the second direction; the second direction is perpendicular to the first direction;

[0016] A slope layer is disposed on the peripheral sides of the piezoelectric layer and the first isolation layer, wherein the slope layer is disposed in contact with at least a portion of the piezoelectric layer and the first edge of the first isolation layer;

[0017] The plane where the top of the slope layer is located is flush with the lower surface of the emission layer, and the plane where the top of the slope layer is located is flush with the upper surface of the first isolation layer.

[0018] Furthermore, along the direction away from the piezoelectric layer, the thickness of the slope layer gradually decreases.

[0019] Furthermore, the slope layer includes a slope, and the slope connects the top and bottom ends of the slope layer;

[0020] The angle formed between the plane where the inclined surface is located and the vertical direction is greater than or equal to 30° and less than or equal to 60°.

[0021] Furthermore, the fingerprint sensor further includes:

[0022] A receiving layer, arranged on a side of the piezoelectric layer away from the transmitting layer;

[0023] The second isolation layer is arranged between the receiving layer and the piezoelectric layer.

[0024] Furthermore, the fingerprint recognition sensor further comprises a receiving layer, and the receiving layer is arranged on a side of the piezoelectric layer away from the transmitting layer;

[0025] The receiving layer includes a plurality of receiving electrodes;

[0026] The orthographic projection of one of the receiving electrodes on the piezoelectric layer only overlaps or partially overlaps with the orthographic projection of one of the transmitting electrodes on the piezoelectric layer.

[0027] Further, the transmitting electrode extends along the second direction; the receiving electrodes are arranged at intervals along the first direction and the second direction; the first direction is perpendicular to the second direction;

[0028] A plurality of the receiving electrodes spaced apart along the second direction form a receiving electrode group, and an orthographic projection of one of the receiving electrode groups on the piezoelectric layer only overlaps with an orthographic projection of one of the receiving electrodes on the piezoelectric layer.

[0029] According to a second aspect of the present application, a display panel is provided, the display panel comprising a display unit and the above-mentioned fingerprint recognition sensor;

[0030] The fingerprint recognition sensor is arranged at one side of the display unit.

[0031] Furthermore, the fingerprint sensor also includes a reflective layer, and the reflective layer is located on a side of the fingerprint sensor away from the display unit.

[0032] Furthermore, the emission layer is arranged on a side of the piezoelectric layer close to the reflection layer, and the reflection layer is grounded.

[0033] Furthermore, the fingerprint recognition sensor further comprises a receiving layer and a signal receiver, and the receiving layer and the signal receiver are electrically connected;

[0034] The receiving layer and the signal receiver are closer to the display unit than the transmitting layer, or the receiving layer and the signal receiver are farther from the display unit than the transmitting layer.

[0035] According to a third aspect of the present application, a method for manufacturing a fingerprint recognition sensor is provided. The method can be used to manufacture the above-mentioned fingerprint recognition sensor. The method comprises:

[0036] providing a substrate;

[0037] forming a piezoelectric layer;

[0038] forming a first isolation layer on the piezoelectric layer;

[0039] An emitting layer is formed on the first isolation layer, wherein the emitting layer includes a plurality of emitting electrodes arranged at intervals; the emitting electrodes extend along a second direction and exceed a first edge of the piezoelectric layer and the first isolation layer in the second direction.

[0040] Furthermore, the production method also includes:

[0041] Before forming the emission layer, a slope layer is formed; at least a portion of the slope layer is arranged in contact with the edges of the piezoelectric layer and the first isolation layer, and a plane where the top of the slope layer is located is flush with an upper surface of the first isolation layer.

[0042] Furthermore, the temperature for forming the slope layer is less than or equal to 110°C.

[0043] The technical solution provided by the embodiments of the present disclosure may have the following beneficial effects:

[0044] By setting up multiple emitting electrodes arranged at intervals, the accuracy of fingerprint recognition can be improved; by setting up an isolation structure, namely a first isolation layer, between the piezoelectric layer and the emitting layer, it is possible to avoid the manufacturing process of the emitting layer including multiple emitting electrodes from damaging the piezoelectric layer, prevent peeling and falling off between the piezoelectric layer and the emitting layer, and maintain the high recognition accuracy of the fingerprint recognition sensor.

[0045] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic cross-sectional structure diagram of a display panel according to an embodiment of the present application.

[0047] Figure 2 It is a schematic diagram of the cross-sectional structure of a fingerprint recognition sensor according to an embodiment of the present application.

[0048] Figure 3 It is a schematic diagram of the planar structure of a fingerprint recognition sensor according to an embodiment of the present application.

[0049] Figure 4 It is another planar structural schematic diagram of a fingerprint recognition sensor according to an embodiment of the present application.

[0050] Figure 5 It is another cross-sectional structural schematic diagram of a fingerprint recognition sensor according to an embodiment of the present application.

[0051] Figure 6 A scanning electron microscope image of the piezoelectric layer of a fingerprint recognition sensor.

[0052] Figure 7 1 is a scanning electron microscope image of the piezoelectric layer of the fingerprint recognition sensor according to an embodiment of the present application.

[0053] Figure 8 It is a simplified flowchart of a method for manufacturing a fingerprint recognition sensor according to an embodiment of the present application.

[0054] Description of Reference Numerals

[0055] Display Panel 1

[0056] Finger 2

[0057] Fingerprint sensor 10

[0058] Routing area 11

[0059] Identification area 12

[0060] Piezoelectric layer 100

[0061] Emission layer 200

[0062] Emitter electrode 210

[0063] Receiving layer 300

[0064] Receiving electrode 310

[0065] Receiving electrode group 320

[0066] Signal Receiver 400

[0067] Crystal diode 410

[0068] Gate 411

[0069] Source 412

[0070] Drain 413

[0071] Semiconductor layer 414

[0072] First isolation layer 610

[0073] First Edge 611

[0074] Second isolation layer 620

[0075] The third isolation layer 630

[0076] Slope layer 700

[0077] Incline 710

[0078] Reflective layer 800

[0079] Flat layer 910

[0080] Protective layer 920

[0081] Dielectric layer 930

[0082] Bottom insulation layer 940

[0083] Base 950

[0084] Plastic layer 960

[0085] Adhesive layer 970

[0086] Display unit 20

[0087] Light-emitting unit layer 21

[0088] Glass cover 22

[0089] Fingerprint 30

[0090] Valley 31

[0091] Ridge 32

[0092] First direction X

[0093] Second direction Y

[0094] Vertical direction Z DETAILED DESCRIPTION

[0095] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices consistent with some aspects of the present application as detailed in the appended claims.

[0096] The terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application. Unless otherwise defined, the technical terms or scientific terms used in this application should be understood by people with ordinary skills in the field to which this utility model belongs. The words "first", "second" and similar words used in the specification and claims of this application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one" or "one" do not indicate a quantitative limit, but indicate that there is at least one, and if only "one" is referred to, it will be separately described. "Multiple" or "several" means two or more. Unless otherwise specified, similar words such as "front", "rear", "lower" and / or "upper" are only for the convenience of explanation, and are not limited to one position or one spatial orientation. Similar words such as "include" or "comprise" mean that the elements or objects appearing in front of "include" or "comprise" cover the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. "Connected" or "connected" and similar words are not limited to physical or mechanical connections, and may include electrical connections, whether direct or indirect. The singular forms "a", "said" and "the" used in this specification and the appended claims are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0097] The embodiments of the present application are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the features of the following embodiments can be combined with each other.

[0098] The present application relates to a display panel. The display panel may be a flexible display panel or a rigid display panel that cannot be deformed. The display panel may be applied to an electronic device. The electronic device may be a display, a mobile phone, a computer, a tablet, an e-book, and a watch with a smart display function. The main concept of the present application is introduced below using a flexible display panel as an example.

[0099] like Figure 1 As shown, the display panel 1 includes a display unit 20 and a fingerprint recognition sensor 10. The fingerprint recognition sensor 10 is disposed on one side of the display unit 20. In this embodiment, the display unit 20 includes a light-emitting unit layer 21 and a glass cover plate 22. The fingerprint recognition sensor 10 and the display unit 20 are bonded by an adhesive layer 970. Specifically, the fingerprint recognition sensor 10 is bonded to the light-emitting unit layer 21 of the display unit 20 by an adhesive layer 970. Among them, the light-emitting layer 21 can be an OLED light-emitting unit.

[0100] The fingerprint recognition sensor 10 is an ultrasonic fingerprint recognition sensor, which can generate vibration and emit a first ultrasonic wave outward. When the user presses the finger 2 on the glass cover 22 at a position corresponding to the fingerprint recognition sensor 10, that is, when the finger 2 is placed above the fingerprint recognition sensor 10, the first ultrasonic wave can reach the user's finger 2, and then the first ultrasonic wave is reflected and forms a second ultrasonic wave. The fingerprint recognition sensor 10 can also receive the second ultrasonic wave and generate an electrical signal corresponding thereto. The fingerprint 30 of the finger is recognized according to the electrical signal. Compared with the optical fingerprint recognition sensor 10, the ultrasonic fingerprint recognition sensor has higher recognition efficiency and accuracy under extreme conditions such as stains on the human finger.

[0101] like Figure 2 If necessary, it can be combined with Figure 3 As shown, the fingerprint recognition sensor 10 may include a piezoelectric layer 100, a transmitting layer 200, a receiving layer 300, a signal receiver 400 and an electrical signal processor (not shown). The transmitting layer 200 and the receiving layer 300 are respectively arranged on both sides of the piezoelectric layer 100. It should be noted that the oblique lines in the figure are only for the convenience of identifying the structure between the layers. The transmitting layer 200 includes a plurality of transmitting electrodes 210 arranged at intervals along the first direction X. The receiving layer 300 includes a plurality of receiving electrodes 310 arranged at intervals.

[0102] The piezoelectric layer 100 is made of piezoelectric material, which can be excited by voltage to produce inverse piezoelectric effect, and can also be excited by vibration to produce positive piezoelectric effect. In this embodiment, the material of the piezoelectric layer 100 is an organic piezoelectric material, such as polyvinylidene fluoride (PVDF) or polypropylene (PP). In other embodiments, the material of the piezoelectric layer 100 can also be an inorganic piezoelectric material, such as piezoelectric ceramics (PZT), piezoelectric crystals, etc.

[0103] The receiving electrode 310 is electrically connected to the signal receiver 400 to transmit the received electrical signal to the signal receiver 400. The signal receiver 400 is electrically connected to the electrical signal processor, which can perform simple processing (e.g., filtering, amplification) on the received electrical signal and send the processed electrical signal to the electrical signal processor. The electrical signal processor receives the processed electrical signal and calculates the user's fingerprint 30 information based on the received electrical signal. The electrical signal processor can be a processing chip.

[0104] When the fingerprint recognition sensor 10 is in working state, the transmitting electrode 210 and the receiving electrode 310 input an alternating voltage (AC voltage) (for example: the transmitting electrode 210 applies an AC square wave, and the receiving electrode 310 is grounded). Then, there is a voltage difference on both sides of the piezoelectric layer 100, and the piezoelectric layer 100 will deform due to the inverse piezoelectric effect or drive the membrane layers above and below the piezoelectric layer 100 to vibrate together, thereby generating a first ultrasonic wave, and the first ultrasonic wave is emitted in a direction away from the piezoelectric layer 100. The first ultrasonic wave emitted by the fingerprint recognition sensor 10 is reflected after reaching the fingerprint 30, and the reflected ultrasonic wave is used as the second ultrasonic wave. After reaching the piezoelectric layer 100, the second ultrasonic wave will drive the piezoelectric layer 100 to deform or vibrate, and due to the positive piezoelectric effect, a voltage difference will be generated on both sides of the piezoelectric layer 100. At this time, the transmitting electrode 210 is grounded, and the receiving electrode 310 can be used to receive electrical signals generated by the positive piezoelectric effect. Since the fingerprint 30 includes valleys 31 and ridges 32 (please refer to Figure 1 ), they have different reflection capabilities for ultrasonic waves (the valley 31 has a stronger reflection capability for ultrasonic waves), resulting in different intensities of ultrasonic waves reflected by the valley 31 and the ridge 32. Therefore, the receiving electrodes 310 at different positions can respectively receive the second ultrasonic waves reflected by the fingerprint 30 at the corresponding position. The electrical signal processor can determine whether the ultrasonic wave is reflected by the valley 31 or the ridge 32 through the voltage received by the receiving electrode 310, thereby realizing fingerprint recognition.

[0105] In this embodiment, the signal receiver 400 includes a plurality of crystal diodes 410. The number of crystal diodes 410 corresponds to the number of receiving electrodes 310, and one crystal diode 410 is electrically connected to a corresponding receiving electrode 310. The crystal diode 410 can filter and amplify the received electrical signal. The filtered and amplified electrical signal is transmitted to the electrical signal processor, which can analyze and calculate the electrical signal processed by the crystal diode 410, and finally obtain the corresponding information related to the fingerprint 30. At the same time, the electrical signal processor is also used to determine whether the obtained fingerprint 30 information corresponds to the preset fingerprint 30 information.

[0106] The crystal diode 410 includes a gate 411, a source 412, a drain 413 and a semiconductor layer 414. The receiving electrode 310 is electrically connected to the input end of the crystal diode 410, the source 412, to transmit the received electrical signal to the signal receiver 400. The output end of the crystal diode 410, the drain 413, is electrically connected to the electrical signal processor to transmit the electrical signal to the electrical signal processor.

[0107] The fingerprint recognition sensor 10 includes a wiring area 11 and an identification area 12. The piezoelectric layer 100 is disposed in the identification area 12. The wiring area 11 is provided with a conductive layer (not shown) electrically connected to the electrical signal processor. In this embodiment, the drain 413 of the crystal diode 410 extends to the conductive layer to be electrically connected to the conductive layer, thereby realizing the electrical connection between the drain 413 and the electrical signal processor.

[0108] The receiving layer 300 is arranged on the side of the piezoelectric layer 100 away from the transmitting layer 200. The orthographic projection of a receiving electrode 310 on the piezoelectric layer 100 only overlaps or partially overlaps with the orthographic projection of a transmitting electrode 210 on the piezoelectric layer 100. The transmitting electrode 210 generates a voltage and applies it to the piezoelectric layer 100. On the one hand, different transmitting electrodes 210 can apply different voltages, so that the first ultrasonic wave generated by the vibration of different positions of the piezoelectric layer 100 is different. The different voltages referred to here can be different voltage thresholds, different periods, different times to generate voltage, etc. On the other hand, the information related to the fingerprint 30 (valley 31 and ridge 32) of the user corresponding to different positions is different. Then, the second ultrasonic wave obtained at different positions is also different. Through the above configuration, one or more receiving electrodes 310 correspond to the same transmitting electrode 210. In other words, the electrical signal formed by the first ultrasonic wave generated by one transmitting electrode 210 after reflection is received by one or more receiving electrodes 310 and calculated by the electrical signal processor connected to the receiving electrode 310, and the fingerprint 30 information at the corresponding position can be accurately obtained. Therefore, it can be avoided that the same receiving electrode 310 receives the electrical signal formed by the first ultrasonic wave generated by the adjacent transmitting electrode 210 after reflection, that is, the crosstalk of the electrical signal is avoided, thereby improving the accuracy of fingerprint 30 recognition.

[0109] Combination Figure 2-Figure 4 As shown, in this embodiment, each transmitting electrode 210 is a strip structure extending along the second direction Y (that is, the second direction Y is the length direction of the transmitting electrode 210). A plurality of receiving electrodes 310 are arranged at intervals along the first direction X and the second direction Y, so that: a plurality of receiving electrodes 310 are arranged in a matrix, and the first direction X and the second direction Y correspond to two sides of the matrix. The first direction X is perpendicular to the second direction Y, and the first direction Z and the second direction Y are both perpendicular to the vertical direction Z. A plurality of receiving electrodes 310 arranged at intervals in the second direction Y form a receiving electrode group 320, and the orthographic projection of one receiving electrode group 320 on the piezoelectric layer 100 only coincides with the orthographic projection of one receiving electrode 310 on the piezoelectric layer 100. Through the above arrangement, the crosstalk phenomenon of the electrical signal generated by the first ultrasonic wave generated by the adjacent transmitting electrodes 210 after reflection through the piezoelectric layer 100 can be better avoided, thereby improving the accuracy of fingerprint 30 recognition. Optionally, each transmitting electrode may be arranged corresponding to one receiving electrode, that is, the orthographic projection of one transmitting electrode on the piezoelectric layer at least partially overlaps with the orthographic projection of one receiving electrode on the piezoelectric layer. Alternatively, each transmitting electrode may be arranged corresponding to two receiving electrodes, that is, the orthographic projection of one transmitting electrode on the piezoelectric layer at least partially overlaps with the orthographic projection of two receiving electrodes on the piezoelectric layer. Alternatively, each transmitting electrode may be arranged corresponding to three receiving electrodes, that is, the orthographic projection of one transmitting electrode on the piezoelectric layer at least partially overlaps with the orthographic projection of three receiving electrodes on the piezoelectric layer.

[0110] The fingerprint recognition sensor 10 may further include an electrical signal generating device (not shown), which is electrically connected to the transmitting layer 200 to control the electrical signal applied to each transmitting electrode 210. A plurality of transmitting electrodes 210 may constitute a plurality of ultrasonic transmitting elements. The electrical signal generating device sequentially applies electrical signals to the transmitting electrodes 210 in a direction pointing from the edge of the piezoelectric layer 100 to the center of the piezoelectric layer 100, so that the ultrasonic wave generated by the piezoelectric layer 100 is focused above the center of the piezoelectric layer 100. By sequentially driving the plurality of transmitting electrodes 210 to achieve the focusing of the ultrasonic wave, on the one hand, the intensity or energy of the emitted ultrasonic wave in a specific area or specific direction can be increased, thereby improving the fingerprint 30 recognition performance; on the other hand, the emitted ultrasonic wave can have better directionality, thereby reducing the crosstalk between the valley 31 and the ridge 32 of the fingerprint 30, thereby improving the fingerprint 30 recognition performance.

[0111] The transmitting electrode 210 extends along the second direction Y and exceeds a portion of the first edge 611 of the piezoelectric layer 100 in the second direction Y and enters the wiring area 11 , and is connected to the electrical signal generating device through the wires in the wiring area 11 .

[0112] In actual use, the user usually places the finger at the center of the identification area 12. The area above the piezoelectric layer 100 is the identification area 12. Then, in this embodiment, the ultrasonic intensity in the area above the center of the piezoelectric layer 100 is increased, that is, the ultrasonic intensity at the center of the identification area 12 is increased, so that the recognition accuracy of the fingerprint recognition sensor 10 can be improved. At the same time, when the fingerprint recognition sensor 10 increases the intensity or energy of the emitted ultrasonic wave in a specific area or specific direction by focusing the ultrasonic wave, the fingerprint recognition sensor 10 can not only realize fingerprint recognition, but also penetrate the finger to distinguish whether the fingerprint is real skin.

[0113] The shape of the emitting electrode 210 may be a strip, a block or other shapes. Figure 3 As shown, in this embodiment, the transmitting electrode 210 is a strip structure extending along the second direction Y. A plurality of transmitting electrodes 210 are arranged at intervals along the first direction X. It is determined through experiments that when the number of the transmitting electrodes 210 is greater than or equal to three, the electrical signal generating device in the fingerprint recognition sensor 10 can better apply different electrical signals to each transmitting electrode 210, and make the ultrasonic wave focused in the designated area, thereby improving the accuracy of fingerprint 30 recognition.

[0114] During the manufacturing process, it is necessary to make the emission layer 200 above the piezoelectric layer 100. Since the emission layer 200 includes a plurality of emission electrodes 210 arranged at intervals, the emission layer 200 usually needs to be obtained by photolithography and etching processes. In the above process, a stripping solution is inevitably used. The components of the stripping solution usually include N-methylformamide (NMF) and / or diethylene glycol monomethyl ether. However, the piezoelectric layer 100 is made of polyvinylidene fluoride (PVDF), which is soluble in N-methylformamide and ethers. In other words, the stripping solution will corrode the piezoelectric layer 100, so that the piezoelectric layer 100 cannot be closely attached to the structural layer below the piezoelectric layer 100. At the same time, since polyvinylidene fluoride is a fluorine-containing material, the adhesion between the piezoelectric layer 100 and the structural layer below it is poor, which causes the piezoelectric layer 100 to easily peel off. Once the piezoelectric layer 100 is peeled off, it not only affects the service life of the fingerprint recognition sensor 10 and its defective rate, but also reduces the recognition accuracy of the fingerprint recognition sensor 10.

[0115] In this embodiment, the fingerprint recognition sensor 10 further includes a first isolation layer 610 and a second isolation layer 620 .

[0116] The first isolation layer 610 is disposed between the piezoelectric layer 100 and the emission layer 200. When the emission layer 200 is formed on the piezoelectric layer 100, due to the isolation effect of the first isolation layer 610, the piezoelectric layer 100 will not be corroded by contact with the stripping liquid, thereby effectively suppressing the peeling and shedding phenomenon caused by the corrosion of the piezoelectric layer 100, thereby improving the life and yield of the fingerprint recognition sensor 10, and at the same time improving the recognition accuracy of the fingerprint recognition sensor 10.

[0117] Furthermore, the dielectric constant of the first isolation layer 610 is greater than or equal to 6, and less than or equal to 9. In the above configuration, the insulation of the first isolation layer 610 is good, which avoids the phenomenon of crosstalk between the electrical signals of the respective transmitting electrodes 210 located above the first isolation layer 610. At the same time, when the dielectric constant of the first isolation layer 610 is within the above range, the polarization process of the piezoelectric layer 100 can be completed after the patterning of the piezoelectric layer 100, or, it can also be completed after the deposition of the first isolation layer 610, which can enrich the polarization process route of the piezoelectric layer 100. In the present embodiment, the material of the first isolation layer 610 is silicon nitride (SiN), and its dielectric constant is between 6.8 and 7.

[0118] The thickness of the first isolation layer 610 is greater than or equal to 1000 angstroms and less than or equal to 6000 angstroms. It has been determined through experiments that when the thickness of the first isolation layer 610 is within the above range, the first isolation layer 610 can play the role of an excellent isolation stripping liquid, and the voltage applied to the piezoelectric layer 100 and the vibration will not be affected due to the excessive thickness of the first isolation layer 610. Furthermore, the first isolation layer 610 can be made by a low-temperature deposition process, which will not affect the polarization process route and piezoelectric performance of the piezoelectric layer 100.

[0119] When the first isolation layer 610 is not provided between the piezoelectric layer 100 and the emitting layer 200, if the potential difference between the emitting layer 200 and the receiving layer 300 is 100V, then the actual voltage difference between the two end surfaces of the piezoelectric layer 100, the maximum displacement of the glass cover plate 22 of the display unit 20 caused by the ultrasonic wave, the difference between the valley 31 and the ridge 32 at the center position, and the specific values ​​of the resonant frequency are shown in Table 1. When the first isolation layer 610 is provided between the piezoelectric layer 100 and the emitting layer 200, and the first isolation layer 610 is 6000 angstroms, 3000 angstroms, and 1000 angstroms respectively, if the potential difference between the emitting layer 200 and the receiving layer 300 is still 100V, then the actual voltage difference between the two end surfaces of the piezoelectric layer 100, the maximum displacement of the glass cover plate 22 of the display unit 20 caused by the ultrasonic wave, the difference between the valley 31 and the ridge 32 at the center position, and the specific values ​​of the resonant frequency are shown in Table 1.

[0120]

[0121] Table 1

[0122] By observing Table 1, it can be seen that when the transmitting electrode 210 is controlled in a time-sequential manner, a focused wave is generated at the center position; when the transmitting electrode 210 is not controlled in a time-sequential manner, the transmitting layer 200 generates a plane wave. The valley-ridge difference at the center position of the focused wave is significantly greater than the valley-ridge difference of the plane wave. It can be seen that the time-sequential control is more conducive to the accurate recognition of the fingerprint recognition sensor 10. At the same time, by observing Table 1, it can be seen that when the thickness of the first isolation layer 610 is larger, the voltage difference between the two end surfaces of the piezoelectric layer 100 will be greatly affected, and it will also affect the valley-ridge difference and the maximum displacement of the glass cover 22, thereby affecting the recognition accuracy of the fingerprint recognition sensor 10 (refer to Figure 1). When the thickness of the first isolation layer 610 is 1000 angstroms, the first isolation layer 610 will still have a certain impact on the voltage applied to the piezoelectric layer 100, but the impact is small. The 1000 angstrom first isolation layer 610 will only reduce the voltage difference by 2%. Such an impact is completely acceptable and can ensure the recognition accuracy of the fingerprint recognition sensor 10, and can isolate the stripping liquid from corroding the emitting electrode 210. When the thickness of the first isolation layer 610 is less than 1000 angstroms, the probability of the stripping liquid being unable to be effectively isolated will increase significantly. Preferably, the thickness of the first isolation layer 610 can be selected to be any value between 1000 angstroms and 2000 angstroms.

[0123] The second isolation layer 620 is disposed between the piezoelectric layer 100 and the receiving layer 300. In the present embodiment, the material of the second isolation layer 620 is the same as that of the first isolation layer 610, both of which are silicon nitride (SiN), and in the present embodiment, the thickness thereof is 5000A. By disposing the second isolation layer 620 between the piezoelectric layer 100 and the receiving layer 300, the influence of the leakage current under the high voltage (above 7.5Kv) of the polarization device on the characteristics of the crystal diode 410 in the signal receiver 400 when the PVDF is polarized can be reduced. At the same time, since silicon nitride needs to be coated in the form of a solution during the process of manufacturing the piezoelectric layer 100. The second isolation layer 620 is disposed above the transmitting electrode layer to prevent the corrosion and oxidation of the transmitting layer 200 by silicon nitride. In addition, the second isolation layer 620 can prevent short circuits between the receiving electrode 310 and the transmitting electrode 210, short circuits between multiple receiving electrodes 310, and the like.

[0124] like Figure 5 As shown, the emitting electrode 210 extends along the second direction Y and exceeds the first edge 611 of the piezoelectric layer 100 and the first isolation layer 610 in the second direction Y. Since the slope of the edge of the piezoelectric layer 100 is relatively large, usually, the slope of the edge of the piezoelectric layer 100 is 90 degrees. At this time, the scanning electron microscope image of the piezoelectric layer is as shown in FIG. Figure 6 If the emitting layer 200 is formed on the piezoelectric layer 100 with a large edge slope, the emitting electrode 210 in the emitting layer 200 is prone to breakage of the emitting electrode 210 at the first edge of the piezoelectric layer 100, or short circuit between the emitting electrode 210 and the electric signal generating device.

[0125] In this embodiment, a slope layer 700 is provided on the peripheral side of the piezoelectric layer 100 and the first isolation layer 610, and the slope layer 700 is provided to contact the first edge 611 of the piezoelectric layer 100 and the first isolation layer 610. The plane where the top of the slope layer 700 is located is flush with the lower surface of the emitting layer 200, and the plane where the top of the slope layer 700 is located is flush with the upper surface of the first isolation layer 610. In the above arrangement, the emitting electrode 210 can be laid on the upper surface of the first isolation layer 610 and the slope layer 700, and the slope layer 700 is in contact with the first edge 611. At this time, the piezoelectric layer and the scanning electron microscope image are as follows: Figure 7 Through the above arrangement, the transmitting electrode 210 is prevented from being directly laid on the edge of the piezoelectric layer 100 and the first isolation layer 610, thereby preventing the transmitting electrode 210 from being disconnected at the first edge of the piezoelectric layer 100 and the first isolation layer 610, and preventing the transmitting electrode 210 from being short-circuited with the electrical signal generating device.

[0126] The slope layer 700 may include a plurality of slope blocks, the number of which corresponds to the number of the emitting electrodes 210, and the slope blocks are disposed only below the emitting electrodes 210. Alternatively, the slope layer 700 may include two slope blocks, which are disposed on opposite sides of the piezoelectric layer 100, that is, the two slope blocks are disposed to cover the first edge 611, and the shape of the slope blocks is a triangular prism. Alternatively, the slope layer 700 may also be an annular hollow structure surrounding the piezoelectric layer 100 and the first isolation layer 610.

[0127] Along the direction away from the piezoelectric layer 100, the thickness of the slope layer 700 gradually decreases. Figure 2 and Figure 5 As shown. Through the above arrangement, the emission layer 200 can achieve a smooth transition through the slope layer 700, avoiding the phenomenon of broken wires and the like due to excessive step differences at different positions of the emission electrode 210. The material of the slope layer 700 includes a curing glue. In the process of forming the slope layer 700, the curing glue has a certain fluidity and ductility after coating and before curing. Therefore, the curing glue will undergo a leveling process, thereby naturally forming the above-mentioned slope layer 700, so that without the need for additional process steps, a structure in which the thickness of the slope layer gradually decreases in the direction from the first edge 611 to the center away from the piezoelectric layer 100 can be formed, thereby reducing the difficulty and cost of production. In this embodiment, the material of the slope layer 700 includes an optical curing glue (OC glue). Then, the slope layer 700 can be patterned directly by an exposure process without using a mask process, thereby further reducing the production cost. For example, the material of the auxiliary structure can be an acrylate system material.

[0128] Furthermore, the slope layer 700 includes a slope 710, which connects the top and bottom of the slope layer 700. The plane where the slope 710 is located forms an angle greater than or equal to 30° with the vertical direction Z, and less than or equal to 60°. Through the advection process of the curing glue, it is easy to obtain a slope with an angle within the above range. At the same time, when the angle between the slope 710 and the vertical direction Z is within the above range, the emitter electrode 210 is not prone to disconnection due to the excessive slope of the slope 710. In addition, the slope layer 700 will not occupy too much area due to the excessively small slope of the slope 710, thereby keeping the range of the routing area 11 within a reasonable range.

[0129] The fingerprint recognition sensor 10 may further include a reflective layer 800, a third isolation layer 630, a flat layer 910, a protective layer 920, a dielectric layer 930, a bottom insulating layer 940, a substrate 950 and a plastic encapsulation layer 960. Figure 2 shown.

[0130] The reflective layer 800 is located on a side of the fingerprint recognition sensor 10 away from the display unit 20. Figure 1 As shown. The ultrasonic wave generated by the piezoelectric layer 100 will radiate toward the side close to the display unit 20, and at the same time, will radiate toward the side far from the display unit 20. By arranging the reflective layer 800 on the side far from the display unit 20, the ultrasonic wave radiated toward the side far from the display unit 20 can be reflected and re-radiated toward the side close to the display unit 20, thereby avoiding the waste of ultrasonic waves. In addition, the ultrasonic wave can also avoid the influence of the ultrasonic wave on the device of the electronic device located on the side of the reflective layer 800 far from the display unit 20. In the present embodiment, the material of the reflective layer 800 can be silver (Ag). The reflective layer 800 is grounded. Through the above arrangement, the formation of capacitance between the reflective layer 800 made of metal material and the receiving layer 300 can be avoided.

[0131] In this embodiment, the receiving layer 300 and the signal receiver 400 are closer to the display unit 20 than the transmitting layer 200. The third isolation layer 630 is arranged between the receiving layer 300 and the reflective layer 800, that is, the transmitting layer 200 is arranged on the side of the piezoelectric layer 100 close to the reflective layer 800. The third isolation layer 630 plays a flattening role, and at the same time, avoids the short circuit between the transmitting electrode 210 and the reflective layer 800. The third isolation layer 630 also fills the gap between adjacent transmitting electrodes 210, thereby avoiding short circuits between multiple transmitting electrodes 210. The material of the third isolation layer 630 is the same as that of the first isolation layer 610 and the second isolation layer 620, both of which are silicon nitride (SiN).

[0132] Of course, in other embodiments, the receiving layer 300 and the signal receiver 400 may be closer to the display unit 20 than the transmitting layer 200 .

[0133] The crystal diode 410 of the signal receiver 400 is disposed above the substrate 950, and the semiconductor layer 414 of the crystal diode 410 is wrapped by the bottom insulating layer 940. The dielectric layer 930 and the gate 411 of the crystal diode 410 are disposed above the bottom insulating layer 940, and the dielectric layer 930 wraps the gate 411. The protective layer 920 is disposed above the dielectric layer 930, and the protective layer 920 wraps the portion of the receiving layer 300 exposed to the dielectric layer 930 and the bottom insulating layer 940. The flat layer 910 is disposed above the protective layer 920. At least part of the receiving layer 300 is disposed above the dielectric layer 930 and is wrapped by the protective layer 920. Another part of the receiving layer 300 penetrates the dielectric layer 930, extends into the bottom insulating layer 940, and is connected to the semiconductor layer 414. The plastic encapsulation layer 960 covers the exposed structure to protect the internal structure of the fingerprint recognition sensor 10.

[0134] like Figure 8 As shown, the present application also discloses a method for manufacturing the fingerprint recognition sensor 10. Figure 2 The production method is introduced. Specifically, the production method comprises the following steps:

[0135] Step 1000: Provide a substrate 950 .

[0136] Step 2000 : forming a signal receiver 400 , a bottom insulating layer 940 and a dielectric layer 930 on a substrate 950 .

[0137] Among them, in this step, it is necessary to first form the semiconductor layer 414 in the signal receiver 400, which can be patterned by photolithography and etching processes. After that, a bottom insulating layer 940 is formed by deposition. Then, a gate metal layer with a certain thickness is formed by a magnetron sputtering process, and then patterned by photolithography and etching processes to obtain a gate 411. Next, a dielectric layer 930 is formed by deposition. Then, a via is realized by photolithography and etching processes. Finally, a source and drain metal layer with a certain thickness is formed by a magnetron sputtering process, and part of the source and drain metal layer enters the via to connect the semiconductor layer 414; then patterned by photolithography and etching processes to obtain a source 412 and a drain 413, respectively. It should be noted that the drain 413 is electrically connected to the electrical signal processor.

[0138] Step 3000 : forming a protection layer 920 on the dielectric layer 930 and the signal receiver 400 by deposition.

[0139] Step 4000: Forming a planarization layer 910 on the protection layer 920 by deposition.

[0140] Step 5000 : forming a receiving layer 300 on the planar layer 910 .

[0141] Among them, it is necessary to first realize vias on the protective layer 920 and the flat layer 910 through photolithography and etching processes, and one end of the via is connected to the source 412 of the signal receiver 400. Then, a receiving metal layer of a certain thickness is deposited by a magnetron sputtering process, at which time, part of the receiving metal layer enters the via and is electrically connected to the source 412. Finally, patterning is achieved through photolithography and etching processes to obtain the receiving layer 300, and the receiving electrode 310 is electrically connected to the source 412 of the corresponding crystal diode 410 to transmit the received electrical signal to the crystal diode 410.

[0142] Step 6000 : forming a second isolation layer 620 on the planar layer 910 and the receiving layer 300 . The second isolation layer 620 may wrap a portion of the receiving electrode 310 located above the planar layer 910 .

[0143] Step 7000 : forming a piezoelectric layer 100 on the second isolation layer 620 .

[0144] Among them, the piezoelectric layer can be made of piezoelectric materials with a high piezoelectric voltage constant such as polyvinylidene fluoride (PVDF). First, a polyvinylidene fluoride (PVDF) solution of a certain thickness is applied at a specific position by a coating machine device (Slot Die). Then, the solvent in the solution is removed by curing at a certain temperature for a period of time. Subsequently, it is crystallized at a certain temperature for a period of time to form more β phases in its structure. After that, it has piezoelectric properties when polarized for a certain period of time under a high voltage electric field. Finally, patterning is achieved through photolithography and etching processes to obtain a piezoelectric layer 100.

[0145] Step 8000 : forming a first isolation layer 610 on the piezoelectric layer 100 .

[0146] Among them, it is necessary to prepare a mask having the same pattern as the piezoelectric layer 100, and then, using the mask and through a deposition process, form a first isolation layer 610 covering the piezoelectric layer 100 on the piezoelectric layer 100. It should be noted that the deposition process of the first isolation layer 610 needs to be carried out at a low temperature, and the low temperature referred to here is not higher than the crystallization temperature of the polyvinylidene fluoride (PVDF) of the piezoelectric layer 100, generally a temperature below 110°C. Through the above setting, the problem of affecting the piezoelectric performance of polyvinylidene fluoride (PVDF) due to excessively high deposition temperature can be avoided.

[0147] Step 9000: An emission layer 200 is formed on the first isolation layer 610, and the emission layer 200 includes a plurality of emission electrodes 210 arranged at intervals. The emission electrodes 210 extend along the second direction Y and exceed the first edge of the piezoelectric layer 100 and the first isolation layer 610 in the second direction Y to electrically connect the electrical signal generating device. The emission metal layer of a certain thickness is deposited by a magnetron sputtering process, and then patterned by photolithography and etching processes to obtain the emission layer 200.

[0148] Step 9100 : forming a third isolation layer 630 above the first isolation layer 610 and the emission layer 200 , wherein the third isolation layer 630 wraps the exposed portion of the emission electrode 210 .

[0149] Among them, a third isolation layer 630 of a certain thickness is deposited by a thin film packaging device. It should be noted that the deposition process of the third isolation layer 630 needs to be carried out at a low temperature, and the low temperature referred to here is not higher than the crystallization temperature of polyvinylidene fluoride (PVDF) of the piezoelectric layer 100, which is generally a temperature below 110°C. In this embodiment, the material of the third isolation layer 630 is silicon nitride. The dielectric constant of silicon nitride is between 6.8 and 7. The polarization process of the piezoelectric layer 100 can be completed after patterning, or it can be completed after the deposition of the second isolation layer 620, or after the deposition of the third isolation layer 630, which can be the polarization process route of the piezoelectric layer 100. Of course, in other embodiments, the material of the third isolation layer 630 can also be an organic negative photoresist (PR glue). However, correspondingly, the polarization process of the piezoelectric layer 100 must be completed before the third isolation layer 630 is formed. It should be noted that the lower surface of the emitting electrode 210 is in close contact with the first isolation layer 610 , and the exposed portion of the emitting electrode 210 refers to the portion of the emitting electrode 210 that does not contact the first isolation layer 610 , namely, the peripheral side of the emitting electrode 210 and its upper surface.

[0150] Step 9200: forming a reflective layer 800 on the third isolation layer 630. In this embodiment, a silver paste of a certain thickness can be prepared by screen printing equipment as the reflective layer 800, and the silver paste also needs to exceed the boundary of the piezoelectric layer 100 and access the wiring area to connect with the ground line to avoid the formation of a capacitor storing potential between the reflective layer 800 made of metal material and the emitter electrode 210.

[0151] Step 9300: Form a plastic layer 960 on the reflective layer 800. The plastic layer 960 wraps the structures in the wiring area 11 and the identification area 12 to protect them. In this embodiment, the plastic layer 960 of a certain thickness can be prepared by screen printing equipment, and its material can be epoxy resin.

[0152] Furthermore, before step 9000 (forming the emission layer 200 on the first isolation layer 610), the following steps may be performed:

[0153] The slope layer 700 is formed. For example, a curing glue layer can be formed by coating a certain thickness of optical curing glue (OC glue) on the first isolation layer 610. Then, patterning is achieved through photolithography and etching processes, thereby removing the optical curing glue on the first isolation layer 610, so that the upper surface of the first isolation layer 610 is exposed, so that the emission layer 200 can be subsequently formed thereon.

[0154] At this time, at least part of the slope layer 700 is arranged in contact with the edge of the piezoelectric layer 100 and the first isolation layer 610, and the plane where the top of the slope layer 700 is located is flush with the upper surface of the first isolation layer 610. Since the signal control line of the electrical signal control device is connected to the transmitting electrode 210 of the transmitting layer 200, the voltage control of the transmitting electrode 210 is realized. The setting of the slope layer 700 can facilitate the connection between the signal control line and the part of the transmitting electrode 210 extending out of the first edge, avoiding the phenomenon of disconnection and short circuit caused by excessive step difference at the first edge of the piezoelectric layer 100. It should be noted that the signal control line can enter the wiring area 11 and be electrically connected to the transmitting electrode 210, or the transmitting electrode 210 can extend out of the wiring area 11 and be electrically connected to the signal control line.

[0155] Furthermore, the temperature for forming the slope layer 700 needs to be less than or equal to 110° C. The temperature for forming the slope layer 700 must not be higher than the crystallization temperature of polyvinylidene fluoride (PVDF) of the piezoelectric layer 100, which is usually 110° C. In this embodiment, the temperature for forming the slope layer 700 is preferably 80° C.-90° C. Through the above arrangement, the process for forming the slope layer 700 can be prevented from affecting the piezoelectric performance of the piezoelectric layer 100.

[0156] After the fingerprint recognition sensor 10 is manufactured, turn the fingerprint recognition sensor 10 upside down and combine it with Figure 1 and Figure 2 As shown, an adhesive layer 970 is coated on the substrate 950. Alternatively, an adhesive layer 970 is coated on the side of the light-emitting unit layer 21 away from the glass cover plate 22. Afterwards, the two are mounted in a box to obtain a display unit 20 with a fingerprint 30 recognition function. The material of the adhesive layer 970 can be OCA (Optically Clear Adhesive) optical glue.

[0157] The above is only a preferred embodiment of the present application and does not constitute any form of limitation to the present application. Although the present application has been disclosed as a preferred embodiment as above, it is not intended to limit the present application. Any technician familiar with the profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present application. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still falls within the scope of the technical solution of the present application.

Claims

1. A fingerprint recognition sensor, characterized in that: The fingerprint recognition sensor comprises: Piezoelectric layer; An emitting layer, arranged on one side of the piezoelectric layer, the emitting layer comprising a plurality of emitting electrodes arranged at intervals; A first isolation layer, disposed between the piezoelectric layer and the emission layer; The transmitting electrode extends along the second direction and exceeds the first edges of the piezoelectric layer and the first isolation layer in the second direction, and the multiple transmitting electrodes are arranged along the first direction; the second direction is perpendicular to the first direction; A slope layer is disposed on the peripheral sides of the piezoelectric layer and the first isolation layer, wherein the slope layer is in contact with the first edge; The thickness of the slope layer gradually decreases in a direction away from the piezoelectric layer; and the plane where the top of the slope layer is located is flush with the lower surface of the emitting layer, and the plane where the top of the slope layer is located is flush with the upper surface of the first isolation layer.

2. The fingerprint recognition sensor according to claim 1, characterized in that: The thickness of the first isolation layer is greater than or equal to 1000 angstroms and less than or equal to 6000 angstroms.

3. The fingerprint recognition sensor according to claim 1, characterized in that: The dielectric constant of the first isolation layer is greater than or equal to 6 and less than or equal to 9; Alternatively, the material of the first isolation layer is silicon nitride.

4. The fingerprint recognition sensor according to claim 1, characterized in that: The number of the transmitting electrodes is greater than or equal to 3.

5. The fingerprint recognition sensor according to claim 1, characterized in that: The fingerprint recognition sensor further includes an electrical signal generating device, the electrical signal generating device being electrically connected to the emission layer to control the electrical signal applied to the emission electrode; The electrical signal generating device is configured to apply electrical signals to each transmitting electrode in sequence along the direction from the edge of the piezoelectric layer to the center of the piezoelectric layer, so that the ultrasonic wave generated by the piezoelectric layer is focused above the center of the piezoelectric layer.

6. The fingerprint recognition sensor according to claim 1, characterized in that: The slope layer comprises a slope connecting the top and bottom ends of the slope layer; The angle formed between the plane where the inclined surface is located and the vertical direction is greater than or equal to 30° and less than or equal to 60°.

7. The fingerprint recognition sensor according to claim 1, characterized in that: The fingerprint recognition sensor also includes: A receiving layer, arranged on a side of the piezoelectric layer away from the transmitting layer; The second isolation layer is arranged between the receiving layer and the piezoelectric layer.

8. The fingerprint recognition sensor according to claim 1, characterized in that: The fingerprint recognition sensor further includes a receiving layer, wherein the receiving layer is arranged on a side of the piezoelectric layer away from the transmitting layer; The receiving layer includes a plurality of receiving electrodes; The orthographic projection of one of the receiving electrodes on the piezoelectric layer only overlaps or partially overlaps with the orthographic projection of one of the transmitting electrodes on the piezoelectric layer.

9. The fingerprint recognition sensor according to claim 8, characterized in that: The transmitting electrode extends along the second direction, and the plurality of transmitting electrodes are arranged along the first direction; the plurality of receiving electrodes are arranged at intervals along the first direction and the second direction; The first direction is perpendicular to the second direction; A plurality of the receiving electrodes spaced apart along the second direction form a receiving electrode group, and an orthographic projection of one of the receiving electrode groups on the piezoelectric layer only overlaps with an orthographic projection of one of the receiving electrodes on the piezoelectric layer.

10. A display panel, characterized in that: The display panel includes a display unit and a fingerprint recognition sensor as claimed in any one of claims 1 to 9.

11. A method for manufacturing a fingerprint recognition sensor, characterized in that: The manufacturing method is used to manufacture the fingerprint recognition sensor according to any one of claims 1 to 9, and the manufacturing method comprises: providing a substrate; forming a piezoelectric layer on the substrate; forming a first isolation layer on the piezoelectric layer; An emitting metal layer is formed on the first isolation layer, and an emitting layer is formed by etching the emitting metal layer. The emitting layer includes a plurality of emitting electrodes arranged at intervals.

12. The method according to claim 11, characterized in that: Before forming the emission layer, forming a slope layer at the edges of the piezoelectric layer and the first isolation layer; The slope layer covers the first isolation layer and the slope layer.

13. The method according to claim 11, characterized in that: The temperature for forming the slope layer is less than or equal to 110°C.

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